“…Thus, the epidemic threshold is associated with this cluster becoming macroscopic, i.e., occupying a finite fraction of the system when L → ∞. Although we did not attempt to measure the basic reproduction number R 0 , i.e., the number of secondary infections that a single infected individual can generate before it dies or becomes cured [9,32,33], the outbreak cluster must be related to it [34]. Indeed, the presence of a percolating cluster above the threshold is the difference between an infection that dies out and the onset of an epidemic.…”